JP2016516986A - Coaxial ion guide - Google Patents

Abstract

Disclosed is a method for mass and / or ion mobility analysis, the method comprising trapping ions in an annular or coaxial ion trap (4) and an annular ion guide (3) from said annular or coaxial ion trap (4). And discharging at least a part of the ions in the axial direction. Ions trapped in the ion trap (4) are distributed over the entire circumference of the annular or coaxial ion trap. As the ions travel along at least a portion of the length of the ion guide, there is no restriction on the movement of the ions around the annular ion guide, and the ions separate axially as they travel along the ion guide.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is based on British Patent Application No. 1304521.6 filed on March 13, 2013 and European Patent Application No. 1319069.7 filed on March 13, 2013, and its Insist on profit. The entire contents of these applications are incorporated herein by reference.

  The present invention relates to a method for mass and / or ion mobility analysis and a mass and / or ion mobility analyzer.

  An ion mobility separator that separates ions according to their ion mobility is known. In order to improve the duty cycle of separation by ion mobility, ions may accumulate in a trap region upstream of the ion mobility analyzer or separator device. Since all ions are stored in this trap region before being released into the drift tube, the space charge capacity of this upstream trap region can ultimately determine the performance of the ion mobility analyzer or separator device. Excessive charge in the trapping area can adversely affect downstream analyzer performance. For example, if the charge capacity of the device is exceeded, ions may be lost from the trap region. Due to the nature of the confinement force provided by the RF confinement field, there may be undesirable mass and / or charge discrimination effects in some of the population of ions lost from the trap region. In addition, there can be fragmentation of molecular ions because the charges in space repel each other, pushing the ions closer to the confining electrode.

  One way to increase the charge capacity is to increase the axial length of the trap region. However, when an axially extended ion packet is introduced into an ion mobility analyzer or separator, the resolution of the downstream ion mobility analyzer or separator is reduced. The best performance is preferably achieved when the actual axial distribution of the packets of ions introduced into the device prior to separation by ion mobility is minimal.

  Accordingly, it would be desirable to provide an improved mass spectrometer and method of mass spectrometry.

According to a first embodiment of the invention, a method of mass and / or ion mobility analysis is provided,
Trapping ions in an annular or coaxial ion trap, wherein the trapped ions are distributed over the entire circumference of the annular or coaxial ion trap;
Discharging at least a portion of the ions axially from the annular or coaxial ion trap into an annular ion guide, wherein the ions are separated axially as they travel along the ion guide, and the ions are ion guide Unrestricted movement of ions around the annular ion guide when traveling along at least a portion of the length of
Changing ions from an ion beam having an annular cross section to an ion beam having a non-circular cross section.

  Because the present invention provides an annular or coaxial ion trap and an annular ion guide, the volume for trapping ions and thus the charge capacity is significantly increased over conventional devices having a generally circular inner cross section. The trap geometry of the present invention maximizes the available space charge capacity and adjusts the ion population to a suitable volume for direct injection into the coaxial ion guide.

  U.S. Patent Application Publication No. 2012/0153140 discloses an ion mobility analyzer that includes an annular storage section disposed upstream of an annular drift tube. In operation, ions are pulsed from the storage section into the drift tube, and then the ions are separated as they pass through the drift tube. In the low resolution mode of operation, ions are trapped by electrodes in the arcuate portion of the drift tube as they travel toward the exit of the drift tube. However, this known device has several drawbacks. For example, as ions travel along the drift tube and are confined within the arc, they undergo a space charge effect. Also, ions in the annular storage portion that do not enter the arcuate portion of the drift tube cannot be removed from the device and are lost.

  According to US 2010/0153140, ions are extracted from the device by a potential difference between an annular conductive strip and an outlet plate having an outlet opening. Ions further away from the exit plate are less affected by the extracted electric field than ions near the exit plate. When the extraction electric field for ions farther away from the extraction plate becomes weaker, the time it takes for ions of the same mobility to exit the device changes, and the ion mobility in terms of time scale and time of separation by ion mobility leaving the device It may be longer than the peak width. Thus, the resolution of the device is poor in such situations.

  US 2010/0153140 also describes that ions are driven against a helical potential barrier so that the ions follow a helical path through the drift tube and are separated along this helical path. A high resolution mode of operation is disclosed. Compared to the axial ion path, the helical path requires a stronger electric field along the device in order to maintain or improve the resolution of the device. This is because the spiral path is longer. Even if the electric field in the spiral separation direction does not exceed the upper limit of the electric field, the axial component of the electric field may exceed the upper limit of the electric field, changing the ion mobility of different species. In addition, if the ions are distributed in a uniform annular shape around the storage section, ions from different annular starting positions will move to the instrument axis when ions are drawn axially into the drift tube. It hits the spiral potential barrier at different positions along. This dramatically increases the initial spatial extent of the ions and can have a significant impact on the resolution that can be achieved by the device.

  The ions are preferably randomly distributed around the ion trap and / or around the ion guide.

  The method preferably includes confining ions axially and / or radially within the annular or coaxial ion trap.

  The annular or coaxial ion trap preferably comprises a plurality of first electrodes, and the method preferably includes RF to confine ions radially within the annular or coaxial ion trap. Alternatively, the method further includes applying an AC voltage to the first electrode.

  The ions are preferably confined radially between the inner and outer electrodes in the annular or coaxial ion trap and / or ion guide, and the RF or AC potential preferably confines the ions radially. In order to be applied to the inner and outer electrodes.

  The ions are preferably confined radially between the inner and outer electrodes in the annular or coaxial ion trap and / or ion guide, each of the inner and outer electrodes preferably separated in multiple axial directions. A divided electrode is provided. The axially adjacent electrodes may be supplied with RF voltages of different phases, preferably antiphase.

  The method uses a quadratic DC potential or other DC potential well along the longitudinal axis of the annular or coaxial ion trap to confine ions in the axial direction within the annular or coaxial ion trap. Applying or maintaining may further be included.

  As described above, ions may be radially confined between inner and outer electrodes in an annular or coaxial ion trap, each of the inner and outer electrodes comprising a plurality of axially separated or divided electrodes. You may prepare. Different DC potentials may be applied to these axially separated or divided electrodes so as to form a quadratic DC potential or other DC potential wells along the longitudinal axial direction.

  The method preferably includes confining ions within the toroidal ion trap region within the annular or coaxial ion trap.

  The method preferably includes cooling the ions and / or reducing the kinetic energy of the ions by collision within the annular or coaxial ion trap.

  Ejecting at least a portion of the ions in the axial direction may include: (i) Amplitude of an axial DC and / or RF potential barrier between the annular or coaxial ion trap and the annular ion guide. And / or (ii) reduce or change the amplitude of the DC and / or RF voltage; and / or (iii) lower or remove the DC potential well or suspicion potential well. And / or (iv) pulling out a DC potential well and converting it to a DC potential.

  The step of axially ejecting at least a portion of the ions preferably comprises applying a DC electric field from an annular or coaxial ion trap so that ions are pulsed axially along the annular ion guide. It may include pulsing.

  Ejecting at least a portion of the ions in the axial direction may include applying one or more transient DC voltages or voltage waveforms to the annular or coaxial ion trap. Preferably, the annular or coaxial ion trap comprises a series of axially divided or separated electrodes, and the step of applying one or more transient DC voltages or voltage waveforms is a continuous electrode of the electrodes. A potential barrier traveling along the ion trap is formed by the DC voltage to drive ions out along the ion trap, including applying one or more DC voltages or voltage waveforms to the To do.

  The annular or coaxial ion trap has a first radius r1, and the annular ion guide has a second radius r2. However, r1> r2, r1 = r2, or r1 <r2.

  The annular ion guide preferably comprises an ion mobility analyzer or separator, and ions are separated according to their ion mobility as they pass along the ion guide. The ion guide preferably includes a gas, and the ions may be driven through the gas such that the ions are separated according to their ion mobility through the gas. Ions may be pulsed into an ion mobility analyzer or separator, traveled through, and detected. The time from when any given ion is pulsed into the analyzer or separator until it is detected may be used to determine the ion mobility of the ion.

  The method may further include applying one or more transient DC voltages to the annular ion guide to drive ions along the axial length of the annular ion guide. Preferably, the ion guide comprises a series of axially divided or separated electrodes, and the step of applying one or more transient DC voltages to the ion guide includes 1 to one of the successive electrodes. In order to drive ions along the ion guide, including applying one or more DC voltages, a potential barrier traveling along the ion guide is formed by the DC voltage.

  The method applies one or more steady DC voltages to the annular ion guide or a steady potential difference along at least a portion of the ion guide to drive ions along the axial length of the annular ion guide. It may further include doing.

  The method may include tunneling the ions toward the end of the annular ion guide, funneled, or otherwise focused.

  The first end of the annular ion guide proximal to the annular or coaxial ion trap preferably has an ion confinement region with an annular cross section, and the second distal end of the ion guide is , May have an ion confinement region having a non-circular, circular, rectangular or other cross-section. The electrode forming the ion guide preferably delivers ions from the annular first end of the ion guide to a second distal end having a non-circular, circular, rectangular or other shape in cross section. Arranged and configured as

  The method may include moving ions from the annular ion guide into an ion tunnel ion guide, an ion focused ion guide, or a multipole rod set ion guide.

  The method applies one or more DC voltages or potentials to one or more portions of the annular ion guide to redistribute the ions in the circumferential direction and form a circumferentially compressed ion beam. May include.

  The method includes forcing ions into at least a portion of the ion guide to force ions into an arcuate portion of the ion guide that extends across the circumference of the ion guide and extends only over a portion of the circumference of the ion guide. It may include applying one or more voltages. At least a portion of the ion guide is preferably the end of the ion guide that is opposite the end that is proximal to the ion trap. The ions are preferably compressed into an arcuate portion of the ion guide and then moved into a downstream device, such as a downstream ion guide, analyzer or detector. By compressing the ions into the arc at the end of the ion guide, the ions can be moved more efficiently into a downstream device having a non-circular cross-section to receive the ions. The ions are preferably compressed into the arcuate portion only at the end of the ion guide. The arcuate portion of the ion guide preferably extends over only <75%, <50%, <30%, <20%, or <10% of the circumference of the ion guide.

  The ion guide preferably comprises one or more electrodes arranged circumferentially around the axis of the ion guide, on which the ions are driven into the arcuate part over the circumferential direction of the ion guide. One or more voltages are applied.

  The plurality of electrodes are preferably arranged circumferentially around the axis of the ion guide, and one or more voltages are applied to these electrodes so as to drive ions into the arcuate portion across the circumferential direction of the ion guide. And / or an electrode with a resistive coating may be arranged circumferentially around the axis of the ion guide and drive the ions into the arcuate part over the circumferential direction of the ion guide As such, one or more voltages may be applied.

  Preferably, the ions are confined radially between the inner and outer electrodes in the annular region of the ion guide. Preferably, a plurality of inner electrodes are arranged circumferentially around the axis of the ion guide and / or a plurality of outer electrodes are arranged circumferentially around the axis of the ion guide. A voltage is applied to one or both of these inner and outer electrodes in order to drive ions into the arcuate portion across the circumferential direction of the ion guide.

  The one or more voltages applied to the electrodes to drive the ions into the arcuate portion are preferably DC voltages, but may be RF suspect potentials.

  The method may include focusing or compressing ions in a focusing region of the ion guide, the focusing region being maintained under reduced pressure relative to a portion of the annular ion guide that is proximal to the ion trap. The The region where ions are compressed into the arcuate portion may be maintained under the reduced pressure.

A portion of the annular ion guide preferably comprises an inner electrode divided in the circumferential direction and / or an outer electrode divided in the circumferential direction,
The method applies ions, preferably within the arcuate portion of the ion guide, by applying different DC potentials and / or different RF potentials to the split inner electrode and / or the split outer electrode. , May include convergence.

  The method comprises applying an angular or tilted DC potential or DC electric field to a portion of the annular ion guide to confine ions to a portion of the annular ion guide volume of the annular ion guide. May be included.

  The method includes applying an axial potential barrier around only a portion of the circumference of the ion guide, wherein the ions are axially along the ion guide in a circumferential region where the barrier is located. And ions may pass axially along the ion guide through the arcuate portion of the ion guide where no barrier is disposed.

  The potential barrier preferably extends at an angle between a direction parallel to the longitudinal axis of the ion guide and a direction perpendicular to the axis such that when the ions move axially along the ion guide, the barrier Is forcibly fed into the arc-shaped portion over the circumferential direction of the ion guide.

  The barrier is preferably formed by applying a DC potential to the electrode forming the ion guide. As described above, the electrodes of the ion guide may be divided circumferentially and / or axially and different potentials may be applied to these electrodes to form a barrier. Alternatively, an AC or RF potential may be applied to the electrode to form a barrier.

  The annular or coaxial ion trap preferably comprises a plurality of inner and outer electrodes and an annular or coaxial ion trap region between the inner and outer electrodes. Alternatively or additionally, the annular ion guide preferably comprises a plurality of inner and outer electrodes and an annular ion guide region between the inner and outer electrodes.

  The annular ion guide comprises a plurality of inner electrodes and a plurality of outer electrodes, and an annular ion guide region between the inner and outer electrodes, the radius of the annular ion guide region being the end of the ion guide proximal to the ion trap. It may decrease and / or increase in the direction from the part to the opposite end of the ion guide.

  The radii of the plurality of inner and outer electrodes that form the annular ion guide are preferably gradually reduced along the axial length of the annular ion guide to form an ion guide region of decreasing radius. Alternatively, the radii of the plurality of inner and outer electrodes forming the annular ion guide preferably increase gradually along the axial length of the annular ion guide to form an ion guide region of increasing radius. .

  The outer diameter of the annular ion guide region in the annular ion guide may be gradually tapered, that is, gradually decreased.

  The method may include maintaining the annular or coaxial ion trap at a first pressure p1 and maintaining the annular ion guide at a second pressure p2. However, p1> p2, p1 = p2, or p1 <p2.

  The method may include implanting ions axially and / or tangentially into the annular or coaxial ion trap.

  The method preferably includes introducing ions into the ion trap along the longitudinal axis of the ion trap.

  The ions are preferably driven by an electric field aligned with the axial direction of the ion guide through the ion guide, and preferably this electric field has only an axial component and no radial component.

The present invention also provides a mass and / or ion mobility analyzer, the analyzer comprising:
An annular or coaxial ion trap arranged and adapted to trap ions; and
An annular ion guide;
A control system,
(I) trap ions in the annular or coaxial ion trap, and distribute ions trapped in the ion trap over the entire circumference in the annular or coaxial ion trap; and (ii) from the annular or coaxial ion trap When an ion is ejected in the annular ion guide in the axial direction at least a portion of the ions in the annular or coaxial ion trap, the ions travel around at least a portion of the length of the ion guide and the ions span the circumference of the annular ion guide. A control system that is arranged and adapted to axially separate as the ions travel along the ion guide;
The analyzer electrode configuration is arranged and configured to change ions from an ion beam having an annular cross section to an ion beam having a non-annular cross section.

  The analyzer is preferably arranged and configured to perform any one of the methods described herein.

  The annular or coaxial ion trap is preferably arranged and adapted to confine ions axially and / or radially within the annular or coaxial ion trap.

  The annular or coaxial ion trap preferably comprises a plurality of first electrodes, and the mass spectrometer is preferably for confining ions radially within the annular or coaxial ion trap. , Arranged and adapted to apply an RF or AC voltage to the first electrode.

  The analyzer is preferably configured to confine ions within a toroidal ion trap region within the annular or coaxial ion trap.

  The annular or coaxial ion trap is preferably arranged and adapted to cool the ions and / or reduce the kinetic energy of the ions by collision within the annular or coaxial ion trap.

  The analyzer preferably has a quadratic or other DC potential along the axial direction of the annular or coaxial ion trap to confine ions in the axial direction within the annular or coaxial ion trap. A device arranged and adapted to apply or maintain the well may be provided.

  The control system may be arranged and adapted to axially eject ions from the annular or coaxial ion trap into the annular ion guide by: (i) the annular or coaxial ion trap and the annular Reducing or removing the amplitude of the axial DC and / or RF potential barrier between the ion guides; and / or (ii) reducing or changing the amplitude of the DC and / or RF voltage; and And / or (iii) lowering, removing or changing a DC potential well or a pseudopotential well; and / or (iv) extracting the DC potential well into a DC potential.

  The control system is preferably arranged and adapted to pulse the DC electric field to eject ions from the annular or coaxial ion trap into the annular ion guide in the axial direction.

  The control system applies one or more transient DC voltages or voltage waveforms to the annular or coaxial ion trap to axially eject ions from the annular or coaxial ion trap into the annular ion guide. It may be arranged and adapted.

  The annular or coaxial ion trap has a first radius r1, and the annular ion guide has a second radius r2. However, r1> r2, r1 = r2, or r1 <r2.

  The annular ion guide preferably comprises an ion mobility analyzer or separator.

  The analyzer is preferably arranged and adapted to apply one or more transient DC voltages to the annular ion guide to drive ions along the axial length of the annular ion guide. Equipment.

  The analyzer is preferably arranged and adapted to apply one or more steady DC voltages to the annular ion guide to drive ions along the axial length of the annular ion guide. Equipment.

  The analyzer may comprise a device that is arranged and adapted to focus, tunnel, focus or otherwise focus ions toward the end of the annular ion guide.

  The first end of the annular ion guide proximal to the annular or coaxial ion trap has an ion confinement region that is annular in cross section, and the second distal end of the ion guide is non-cross-sectional. It may have an ion confinement region that is annular, circular, rectangular or otherwise.

  The analyzer may comprise a device arranged and adapted to move ions from the annular ion guide into an ion tunnel ion guide, ion focused ion guide, or multipole rod set ion guide.

  The analyzer is arranged and adapted to apply one or more DC voltages or potentials to one or more portions of the annular ion guide to redistribute ions and form a compressed ion beam. A device may be provided.

  The analyzer may also comprise a device arranged and adapted to reduce the pressure in the ion focusing region of the ion guide relative to the portion of the annular ion guide proximal to the annular or coaxial ion trap. Good.

  A portion of the annular ion guide preferably comprises one or more segmented inner electrodes and / or one or more segmented outer electrodes, and the control system preferably comprises the one or more segmented ion electrodes. Are further arranged and adapted to focus ions by applying different DC potentials and / or different RF potentials to the divided inner electrodes and / or the one or more divided outer electrodes.

  The control system applies an angular or tilted DC potential or DC electric field to a portion of the annular ion guide to confine ions to a portion of the annular ion guide volume of the annular ion guide. May be arranged and adapted to.

  The annular or coaxial ion trap preferably comprises a plurality of inner and outer electrodes and an annular or coaxial ion trap region between the inner and outer electrodes.

  The annular ion guide preferably includes a plurality of inner electrodes and a plurality of outer electrodes, and an annular ion guide region between the inner and outer electrodes.

  The radii of the plurality of inner electrodes forming the annular ion guide may be gradually decreased along the axial length of the annular ion guide.

  The outer diameter of the annular ion guide volume in the annular ion guide may gradually taper, that is, gradually decrease.

  The analyzer may comprise a device arranged and adapted to maintain the annular or coaxial ion trap at a first pressure p1 and the annular ion guide at a second pressure p2. However, p1> p2, p1 = p2, or p1 <p2.

  The analyzer may comprise a device arranged and adapted to inject ions axially and / or tangentially into the annular or coaxial ion trap.

According to a second embodiment, the present invention provides a method for mass and / or ion mobility analysis,
Trapping ions in an annular or coaxial ion trap;
Discharging at least a portion of the ions from the annular or coaxial ion trap into an annular ion guide in the axial direction.

  The ions are preferably randomly distributed around the ion trap and / or around the ion guide.

  The method may include any one or any combination of any two or more of the above features associated with the first embodiment of the present invention.

  The ions trapped in the ion trap are preferably distributed over the entire circumference of the annular or coaxial ion trap.

  As the ions travel along the ion guide, the movement of the ions around the annular ion guide is preferably not limited.

  The ions are preferably separated axially as they travel along the ion guide.

  The method preferably includes changing ions from an ion beam having an annular shaped cross section to an ion beam having a non-annular shaped cross section. The ion guide may be configured to change the shape of the ion beam as it approaches the exit of the ion guide.

According to a second embodiment of the present invention, there is further provided a mass and / or ion mobility analyzer, the analyzer comprising:
An annular or coaxial ion trap arranged and adapted to trap ions; and
An annular ion guide;
A control system,
(I) trap ions in the annular or coaxial ion trap; and (ii) axially direct at least some of the ions in the annular or coaxial ion trap from the annular or coaxial ion trap into an annular ion guide. So that
And a control system to be arranged and adapted.

  The analyzer is preferably arranged and configured to perform any one or any combination of any two or more of the methods described herein.

  For example, the electrode of the ion guide may be arranged and configured to change the shape of the ion beam from an annular shaped cross section to an ion beam having a non-annular cross section as it approaches the exit of the ion guide.

According to another embodiment of the present invention, there is provided a method for storing and implanting ions in an RF confined coaxial ion guide or coaxial ion trap,
(A) accumulating ions in an annular volume with a toroidal ion trap or ion trap region where the ions are randomly distributed;
(B) cooling an accumulated population of ions or reducing kinetic energy by collision with a buffer gas;
(C) discharging the accumulated ions into the coaxial geometry ion guide as an annulus.

  The method may include any one or any combination of any two or more of the features described herein relating to the first embodiment of the invention.

  The toroidal ion trap is preferably part of the same structure as the coaxial ion guide.

  The coaxial ion guide may comprise an ion mobility analyzer or separator (“IMS”) separator.

  Ejection may be achieved by rapidly applying a pulsed DC acceleration electric field.

  Ejection may be achieved by applying a traveling DC wave or one or more transient DC voltage waves.

According to an embodiment, the analyzer is
(A) an ion source selected from the group consisting of: (i) an electrospray ionization (“ESI”) ion source; (ii) an atmospheric pressure photoionization (“APPI”) ion source; (iii) an atmospheric pressure chemical ionization. ("APCI") ion source; (iv) matrix-assisted laser desorption ionization ("MALDI") ion source; (v) laser desorption ionization ("LDI") ion source; (vi) atmospheric pressure ionization ("API") (Vii) ion source on silicon (“DIOS”) ion source; (viii) electron impact (“EI”) ion source; (ix) chemical ionization (“CI”) ion source; (x ) Field ionization (“FI”) ion source; (xi) field desorption (“FD”) ion source; (xii) inductively coupled plasma (“ICP”) ion source; (xiii) fast atom bombardment. ("FAB") ion source; (xiv) liquid secondary ion mass spectrometry ("LSIMS") ion source; (xv) desorption electrospray ionization ("DESI") ion source; (xvi) nickel 63 radiation ion source; xvii) atmospheric pressure matrix assisted laser desorption ionization ion source; (xviii) thermospray ion source; (xix) atmospheric sampling glow discharge ionization (“ASGDI”) ion source; (xx) glow discharge (“GD”) ion source; (Xxi) impactor ion source; (xxii) real-time direct analysis (“DART”) ion source; (xxiii) laser spray ionization (“LSI”) ion source; (xxiv) sonic spray ionization (“SSI”) ion source; (Xxv) Matrix-assisted inlet ionization (“MAII”) And (xxvi) a solvent assisted inlet ionization (“SAII”) ion source; and / or (b) one or more continuous or pulsed ion sources; and / or (c) one or more ion guides; And / or (d) one or more ion mobility separators and / or one or more asymmetric field ion mobility analyzer devices; and / or (e) one or more ion traps or one or more ion traps. And / or (f) one or more collision cells, fragmentation cells or reaction cells selected from the group consisting of: (i) a collision induced dissociation (“CID”) fragmentation device; (ii) surface induced dissociation ( (SID)) fragmentation device; (iii) electron transfer dissociation (“ETD”) fragmentation device; (iv) electron capture Dissociation ("ECD") fragmentation device; (v) electron impact or impact dissociation fragmentation device; (vi) photo-induced dissociation ("PID") fragmentation device; (vii) laser induced dissociation fragmentation device; (viii) infrared induced dissociation device (Ix) UV-induced dissociation device; (x) Nozzle and skimmer interface fragmentation device; (xi) In-source fragmentation device; (xii) In-source collision-induced dissociation fragmentation device; (xiii) Heat source or temperature source fragmentation device; (xiv) (Xvi) Enzymatic digestion or enzymatic fragmentation apparatus; (xvii) Ion ion reaction fragmentation; (Xviii) ion molecule reaction fragmentation device; (xix) ion atom reaction fragmentation device; (xx) ion metastable ion reaction fragmentation device; (xxi) ion metastable molecular reaction fragmentation device; (xxii) ion metastable atom Reaction fragmentation apparatus; (xxiii) ion ion reaction apparatus for reacting ions to form addition ions or product ions; (xxiv) ion-molecule reaction for reacting ions to form addition ions or product ions An apparatus; (xxv) an ion atom reaction apparatus for reacting ions to form adduct ions or product ions; (xxvi) reacting ions to form adduct ions or product ions (Xxvii) ion metastable molecular reactor for reacting ions to form adduct ions or product ions; (xxviii) reacting ions to produce adduct ions or product ions An ion metastable atomic reactor to form; and (xxix) an electron ionization dissociation (“EID”) fragmentation device; and / or (g) a mass spectrometer selected from the group consisting of: (i) a quadrupole (Ii) a 2D or linear quadrupole mass spectrometer; (iii) a pole or 3D quadrupole mass spectrometer; (iv) a Penning trap mass spectrometer; (v) an ion trap mass spectrometer; ) A magnetic field sector mass spectrometer; (vii) an ion cyclotron resonance (“ICR”) mass spectrometer; ) Fourier transform ion cyclotron resonance (“FTICR”) mass spectrometer; (ix) electrostatic field or orbitrap mass spectrometer; (x) Fourier transform electrostatic field or orbitrap mass spectrometer; (xi) Fourier transform mass spectrometer; (Xii) a time-of-flight mass spectrometer; (xiii) an orthogonal acceleration time-of-flight mass spectrometer; and (xiv) a linear acceleration time-of-flight mass spectrometer; and / or (h) one or more energy analyzers or statics And / or (i) one or more ion detectors; and / or (j) one or more mass filters selected from the group consisting of: (i) a quadrupole mass filter; ii) a 2D or linear quadrupole ion trap; (iii) a pole or 3D quadrupole ion trap; (iv) a Penning ion trap; (vi) an ion trap; (vi) a magnetic sector mass filter; (vii) a time-of-flight mass filter; and (viii) a Wien filter; and / or (k) a device or ion gate that delivers ions in pulses; and / or (L) You may further provide the apparatus which changes a substantially continuous ion beam into a pulsed ion beam.

The analyzer may further include any of the following.
(I) C trap and orbitrap (registered trademark) mass spectrometer, comprising an outer barrel electrode and a coaxial inner spindle electrode; in a first mode of operation, after ions are sent to the C trap Injected into the Orbitrap® mass spectrometer and in the second mode of operation, ions are sent to the C trap and then to the collision cell or electron transfer dissociator, where at least some ions are A C trap and an Orbitrap® mass spectrometer that are fragmented into fragment ions and then sent to the C trap before being injected into the Orbitrap® mass spectrometer; and And / or (ii) a laminated ring structure ion guide comprising a plurality of electrodes each having an opening through which ions are passed in use; The distance of the electrode guide increases along the length of the ion path, the electrode opening upstream of the ion guide has a first diameter, and the electrode opening downstream of the ion guide is greater than the first diameter. A laminated ring structure ion guide having a second diameter that is also smaller, and in use, an anti-phase AC or RF voltage is applied to successive electrodes.

  The analyzer may comprise a device that is arranged and adapted to supply an AC or RF voltage to the electrodes. The AC or RF voltage preferably has an amplitude selected from the group consisting of: (i) <50V peak-to-peak; (ii) 50-100V peak-to-peak; (iii) 100-150V peak-to-peak. (Iv) 150-200V peak-to-peak; (v) 200-250V peak-to-peak; (vi) 250-300V peak-to-peak; (vii) 300-350V peak-to-peak; (viii) 350-400V peak-to-peak (Ix) 400-450V peak-to-peak; (x) 450-500V peak-to-peak; and (xi)> 500V peak-to-peak.

  The AC or RF voltage preferably has a frequency selected from the group consisting of: (i) <100 kHz; (ii) 100-200 kHz; (iii) 200-300 kHz; (iv) 300-400 kHz; v) 400-500 kHz; (vi) 0.5-1.0 MHz; (vii) 1.0-1.5 MHz; (viii) 1.5-2.0 MHz; (ix) 2.0-2.5 MHz; (X) 2.5-3.0 MHz; (xi) 3.0-3.5 MHz; (xii) 3.5-4.0 MHz; (xiii) 4.0-4.5 MHz; (xiv) 4.5 (Xv) 5.0-5.5 MHz; (xvi) 5.5-6.0 MHz; (xvii) 6.0-6.5 MHz; (xviii) 6.5-7.0 MHz; xix) 7.0-7.5 MHz; x) 7.5-8.0 MHz; (xxi) 8.0-8.5 MHz; (xxii) 8.5-9.0 MHz; (xxiii) 9.0-9.5 MHz; (xxiv) 9.5 10.0 MHz; and (xxv)> 10.0 MHz.

  The preferred embodiment relates to an improved method of ion accumulation and ion pulse or packet injection into a coaxial RF confined ion guide.

  According to a preferred embodiment, a toroidal ion trap region of similar or the same radial dimensions as the coaxial ion guide is provided in the first trap to adjust the ion population and then to ionize the remaining annulus of ions. It may be quickly injected into the guide. The trapped ions can preferably fill the entire toroidal volume.

  The toroidal trap geometry preferably maximizes the available space charge capacity and adjusts the ion population to a suitable volume for direct injection into the coaxial ion guide.

  In a preferred embodiment, the coaxial RF confined ion guide preferably comprises an ion mobility analyzer or separator, where the ions use a DC electric field or one or more transient DC voltages or DC traveling voltage waves. Driven from the inlet to the outlet end.

  Various embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

It is a figure which shows the toroidal ion trap area | region by embodiment of this invention. It is a figure which shows the coaxial ion mobility analyzer containing an upstream toroidal ion trap area | region. Here, ions are confined in the ion trap region. It is a figure which shows the coaxial ion mobility analyzer containing a toroidal ion trap area | region. Here, ions are released from the ion trap region into the ion mobility analyzer. It is a figure which shows embodiment which makes an ion converge at the exit of an ion guide. FIG. 6 is a cross-sectional view of an embodiment arranged to focus ions at the exit of an ion guide. FIG. 6 shows another embodiment in which the coaxial ion guide is tapered.

  FIG. 1 shows a perspective view of a toroidal ion trap region according to an embodiment of the present invention. The ion trap preferably comprises an inner set of axially separated electrodes 2 and an outer set of axially separated electrodes 1, which together define an annular ion trap volume 3. To do. Opposite phases of the RF frequency AC potential or voltage are preferably applied to the axially alternating electrodes of the inner 2 and outer 1 electrode arrays to provide radial ionization within the annular ion trap volume 3. An annular suspicious potential trap region is formed that acts to confine each other.

  FIG. 1 also shows a plot of the electrical potential as a function of distance along the axial length of the ion trap, preferably for the subset of electrodes on the inner electrode array 2 and the outer electrode array 1. Fig. 4 shows a preferred form of an applied axial DC trapping potential. Different DC potentials may be applied to electrodes in different axial directions so as to form a trap potential. The axial DC trapping potential provides a confining force in the axial direction for ions. Ions may be implanted into the trap region 3 from an external ion source. In the trap region, the ions are preferably confined radially between the outer electrode 1 and the inner electrode 2 by a pseudopotential well, and more preferably axially confined by a DC potential well. The trapped ions are preferably reduced in kinetic energy (ie, cooled) due to collisions with the background gas. The ion cloud 4 preferably takes a random position around the annular or toroidal trap volume, as shown.

  FIG. 2 shows a side view of an embodiment of the present invention comprising a coaxial ion mobility analyzer or separator (“IMS”) drift tube that incorporates an upstream ion trap region of the type shown in FIG. The inner electrode 2 and the outer electrode 3 preferably confine ions in the radial direction as shown. This is accomplished by applying an RF voltage to the inner 2 and outer 3 electrodes. As described with reference to FIG. 1, ions are initially trapped in the toroidal trap region at the inlet end of the device. When enough ions have accumulated, the ions are delivered in pulses from the trap region 4 into the IMS drift tube. Ions cross the drift tube and separate according to their ion mobility. The ions may be detected after exiting the drift tube, or the time from pulse delivery to detection of any given ion may be used to calculate the ion mobility for that ion. Preferably, the ions are periodically pulsed from the trap region 4 into the drift tube. Ions are preferably accumulated in the trap region 4 during the period between any two subsequent ion pulses, i.e. during the time that the previous ion population crosses the ion guide.

  FIG. 2 also shows a plot of electrical potential as a function of distance along the device. The DC potential is indicated by a solid line. Ions enter the device and are preferably prevented from traveling into the ion guide region by applying a DC barrier. Thereby, ions are trapped in the ion trap region 4. Ions from the previously trapped and ejected packet are preferably applied by applying a DC traveling wave or one or more transient DC voltages that drive the ions through the ion guide, as indicated by the dotted lines. It is driven in the ion guide. These ions are preferably separated and eluted in order of their ion mobility.

  FIG. 3 shows the same device as in FIG. 2 during the period in which the accumulated toroidal ion packets are released into the ion guide. At this time, the DC barrier in the trap region 4 is reduced, and a second DC transient (shown in dotted lines) is applied to the electrode in the ion trap region 4 to drive the packet of ions into the ion guide. Yes. The ions are then driven through the ion guide by a DC transient as described with respect to FIG. As ions are pumped into the ion guide, the DC barrier is reapplied or re-established, and additional ions are preferably accumulated. In this way, a high charge density can be achieved with a high duty cycle and high sensitivity.

  According to an alternative embodiment, the trapping region 4 may comprise a separate device rather than being part of the same device at the same pressure, and may be held at a different pressure than the ion guide. A working exhaust opening may be provided between the trap region and the ion guide to enable this.

  It is contemplated that ions can be driven with a DC voltage gradient rather than a traveling DC voltage or one or more transient DC voltage waves.

  Ions may be introduced into the trap region 4 tangential to the circumference of the annular guide, or alternatively along the longitudinal axis.

  A method of focusing ions at the exit of the device is also contemplated herein. The present invention maintains a high space charge capacity by introducing a packet of ions into a coaxial ion guide and separating them inside, while at the same time distributing the ions within the entire annular volume. And it is often desirable to connect a suitable device with other downstream devices. In particular, the downstream devices may not have the same cross-sectional shape as the annular ion guide, and thus the method of connecting the coaxial ion guides to these downstream devices is particularly advantageous. For example, if ions are separated in a coaxial ion mobility analyzer or separator device, the separated ions may be directed to a conventional ion guide having a substantially circular internal cross section.

  One way to accomplish this is to reduce the diameter of the internal annular cross section towards the outlet of the device. For example, the inner and outer electrode diameters may be reduced towards the outlet of the device. The inner electrode diameter may be reduced to substantially zero at the outlet of the device.

  An alternative method is disclosed, which does not depend on physically changing the dimensions of the device. This method applies a DC electric field gradient to a coaxial ion guide that acts in a direction substantially orthogonal to the main direction of ion travel so that this portion of ions is redistributed to occupy a smaller arcuate trap region. Application to a part of the. The DC electric field is preferably directed so that once the ions enter this region, they are compressed into a volume or cross-sectional area suitable for subsequent movement into a device having a non-coaxial geometry. Arranged to be. With this technique, ions may be repositioned so that they are placed in two or more separate arcs spaced circumferentially around the device. This can be useful, for example, to deliver ions to different downstream devices at the outlet of the coaxial ion guide.

  FIG. 4 shows a representation of a coaxial ion guide in the y, z plane, along with the outer electrode 1 and the inner electrode 2. The position 4 of the trapped ions is shown in the toroidal trap region 5 as described above. Ions are preferably injected from the ion trap region 5 into the ion guide or ion mobility analyzer or separation region 6 and travel in the z direction along the axial length of the ion guide. Through the trap 5 and the ion guide region 6, ions are distributed substantially randomly in the annular volume between the inner 2 and outer 1 electrodes. The ions then preferably enter the convergence region 7, where a DC potential is preferably applied in the y direction to force the ions from the lower part of the annular volume to the upper part. Is done. This redistribution occurs as ions travel along the z-axis of the device. The ions exit the device as a compressed beam into the arc of the device, rather than an annulus, so that the ions can be efficiently directed into the conventional ion guide 8.

  As described above, ions may be driven in the z direction by a DC electric field or traveling waves.

  The focusing region 7 may comprise a portion of the ion guide 6 and may be held at the same pressure, or alternatively, a separate region separated by working exhaust openings that are held at different pressures. It may be. If the pressure in the region is different, for example, if the pressure in the IMS cell 6 is 2 mbar and the pressure in the convergence region 7 is 0.005 mbar, the ions in the convergence region 7 are accompanied by a significant deformation of the IMS peak width or shape. Instead, it quickly moves to a position in the desired region of the annular trap volume.

  FIG. 5 shows a cross section passing through the convergence region 7 of FIG. 4 in the y and z planes. Each of the inner 2 and outer electrodes 1 is preferably divided into segment pairs 9, 10, 11, 12, 13. The relative potential applied to each of these electrodes is shown on the plot of potential versus segment number. It can be seen that the potential applied to the segment decreases as the segment number increases. In other words, the potential applied to the segment gradually decreases around the circumference of the device from a maximum value on one side of the device to a minimum value on the opposite side of the device. As a result, a potential difference in which ions are forcibly sent from the maximum potential region to the minimum potential region in the circumferential direction around the apparatus is set. Thus, the ions take the form of a compressed beam centered around the minimum potential in the arc of the device. This configuration provides a driving force that redistributes ions in a small area of the annular volume of the ion guide where ions can be easily extracted.

  Other electrode configurations that provide similar effects are also contemplated. This technique can also be used to force ions to other regions or regions of the annular trap volume. A driving force other than the above-described DC potential gradient may be used. For example, an RF voltage may be applied to the electrodes, and the amplitude of the RF voltage may be different in different segments, resulting in a suspicious potential driving force.

  Another method for driving ions to a desired circumferential position in the device applies one or more potentials to the divided electrodes so that a sloped DC barrier is formed in the convergence region 7 of the device. That is. Ions that cannot cross the barrier are driven to move along the barrier by an axial driving force toward the extraction region. FIG. 6 shows a representation of such an embodiment, showing a coaxial ion guide 6 that is tapered to reduce the radius of the annular trap region in front of the extraction region 7. For illustration purposes, a DC barrier 14 in the extraction region 7 is shown along with a representation of the ion path. The ions are preferably driven along this barrier to the outlet. The barrier blocks the axial movement of the ions except for movement in the upper arc of the device. As ions are forced along the device, they ride on the barrier toward the upper arc. The ions are then compressed into this upper arc. Because there is no barrier in the upper arc, the ions can travel with the compressed ion beam to the exit of the device, which can be useful for subsequent extraction and delivery into another device.

  Although the invention has been described with reference to preferred embodiments, those skilled in the art will make various changes in form and detail without departing from the scope of the invention as set forth in the appended claims. You should understand that you get.

  For example, while an annular ion guide has been described herein as forming an ion mobility analyzer, the advantages of the present invention are also found when the annular ion guide forms part of other types of devices. Provided. In particular, this configuration is also advantageous to avoid space charge effects in other devices.

Claims (29)

A method of mass and / or ion mobility analysis comprising:
Trapping ions in an annular or coaxial ion trap, wherein the trapped ions are distributed over the entire circumference of the annular or coaxial ion trap;
Discharging at least a portion of the ions axially from the annular or coaxial ion trap into an annular ion guide, wherein the ions are separated axially as they travel along the ion guide; Unrestricted movement of ions around the annular ion guide as it travels along at least a portion of the length of the ion guide;
Changing said ions from an ion beam having an annular cross section to an ion beam having a non-circular cross section;
Including a method.   The method of claim 1, wherein the ions are randomly distributed across the circumference of the ion trap and / or around the ion guide.   The ions are radially confined between inner and outer electrodes in the annular or coaxial ion trap and / or the ion guide, and an inner RF or AC potential is used to radially confine the ions. The method according to claim 1, wherein the method is applied to the outer electrode.   The ions are confined radially between inner and outer electrodes in the annular or coaxial ion trap and / or the ion guide, each of the inner and outer electrodes being separated or divided into a plurality of axial directions The method according to claim 1, comprising:   5. A method as claimed in any one of claims 1 to 4, wherein in the annular or coaxial ion trap, in order to confine ions in the axial direction, along the longitudinal axial direction of the annular or coaxial ion trap. 5. The method of claim 1, comprising applying or maintaining a quadratic DC potential or other DC potential well.   6. The method of any one of claims 1-5, comprising cooling ions and / or reducing ion kinetic energy by collision within the annular or coaxial ion trap. The method of any one of claims 1-5.   7. The method according to any one of claims 1 to 6, wherein the step of ejecting at least a portion of the ions in the axial direction is between (i) the annular or coaxial ion trap and the annular ion guide. Reducing or removing the amplitude of the axial DC and / or RF potential barrier; and / or (ii) reducing or changing the amplitude of the DC and / or RF voltage; and / or (iii). 7. A method according to any one of the preceding claims, comprising lowering, removing or changing a DC potential well or a suspicious potential well; and / or (iv) changing a DC potential well to a drawn DC potential. . A method according to any one of claims 1-7,
The step of ejecting at least a portion of the ions in the axial direction is preferably performed so that ions are pulsed axially along the annular ion guide from the annular or coaxial ion trap. Including pulsing the electric field,
8. The method of claim 1, wherein the step of axially ejecting at least a portion of the ions includes applying one or more transient DC voltages or voltage waveforms to the annular or coaxial ion trap. The method described in 1.   9. The annular ion guide comprises an ion mobility analyzer or separator, and the ions are separated according to their ion mobility as they pass along the ion guide. The method described in 1. A method according to any one of claims 1 to 9, comprising
Applying one or more transient DC voltages to the annular ion guide to drive ions along the axial length of the annular ion guide;
Applying one or more steady DC voltages to the annular ion guide or a steady potential difference along at least a portion of the ion guide to drive ions along the axial length of the annular ion guide 10. The method according to any one of claims 1 to 9, comprising:   11. A method according to any one of the preceding claims, wherein ions are preferably tunneled, focused or otherwise directed towards the end of the annular ion guide after the ions have been separated axially. The method according to claim 1, comprising converging with the method.   A first end of the annular ion guide proximal to the annular or coaxial ion trap has an ion confinement region that is annular in cross section, and a second distal end of the ion guide is non-cross sectioned. 12. A method according to any one of the preceding claims having an ion confinement region that is annular, circular, rectangular or otherwise.   The step of changing the ions from an ion beam having an annular cross section includes changing the ions from an ion beam having an annular cross section to an ion beam having a substantially circular, rectangular, or square cross section. The method of any one of Claims 1-12.   14. The method according to any one of claims 1 to 13, wherein the ion tunnel ion guide; ion focused ion guide; multipole rod set ion guide; mass analyzer; mass filter; time-of-flight mass spectrometer; An analyzer; an apparatus for receiving the ions in an ion guide region having a non-annular cross section; or one of the apparatuses for receiving the ions in an ion guide region having a substantially circular, square or rectangular cross section. 14. A method according to any one of the preceding claims comprising moving ions from the annular ion guide.   15. A method according to any one of the preceding claims, wherein one of the annular ion guides is used to redistribute ions in the circumferential direction and form a circumferentially compressed ion beam. 15. A method according to any one of the preceding claims, comprising applying one or more DC voltages or potentials to the above portions.   16. The method according to any one of claims 1 to 15, wherein the ion guide circle extends over only a part of the circumference of the ion guide over a circumferential direction of the ion guide. 16. A method according to any one of the preceding claims, comprising applying one or more voltages to at least a portion of the ion guide to force it into an arcuate portion.   The ion guide includes one or more electrodes arranged circumferentially around the axis of the ion guide, and these electrodes drive ions into the arcuate portion across the circumferential direction of the ion guide. The method of claim 16, wherein one or more voltages are applied. 18. A method according to any one of claims 16 or 17, comprising
A plurality of electrodes are disposed circumferentially around the axis of the ion guide, and one or more voltages are applied to the electrodes to drive ions into the arcuate portion across the circumferential direction of the ion guide. And / or an electrode having a resistive coating is disposed circumferentially about the axis of the ion guide to drive ions into the arcuate portion across the circumferential direction of the ion guide. The method according to claim 16, wherein one or more voltages are applied to the electrode.   19. The method according to any one of claims 1 to 18, comprising focusing or compressing ions in a convergence region of the ion guide, wherein the convergence region is proximal to the ion trap. 19. A method according to any one of the preceding claims, wherein the method is maintained under reduced pressure for a portion of the annular ion guide.   A portion of the annular ion guide comprises a circumferentially divided inner electrode and / or a circumferentially divided outer electrode, and the method comprises the divided inner electrode and / or the divided electrode 20. The method of any of claims 1-19, further comprising focusing ions, preferably within the arcuate portion of the ion guide, by applying different DC potentials and / or different RF potentials to the outer electrode. 2. The method according to item 1.   21. The method of any one of claims 1-20, comprising applying an axial potential barrier around only a portion of the circumference of the ion guide, wherein the ions are in the barrier. In the circumferential region where the ion is not allowed to pass axially along the ion guide and through the arcuate portion of the ion guide where the barrier is not disposed, 21. A method according to any one of claims 1 to 20, wherein the method allows it to pass axially along the ion guide.   The potential barrier extends at an angle between a direction parallel to a longitudinal axis of the ion guide and a direction perpendicular to the axis, so that the ions move axially along the ion guide; The method of claim 21, wherein a barrier is forced into the arcuate portion across the circumferential direction of the ion guide.   The annular ion guide comprises a plurality of inner electrodes and a plurality of outer electrodes, and an annular ion guide region between the inner and outer electrodes, the radius of the annular ion guide region being proximal to the ion trap 23. A method according to any one of the preceding claims, wherein the method decreases and / or increases in the direction from the end of the ion guide to the opposite end of the ion guide.   24. A method according to any one of claims 1 to 23, comprising introducing ions into the ion trap along a longitudinal axis of the ion trap. The method according to claim 1.   The ions are driven through the ion guide by an electric field aligned with the axial direction of the ion guide, and preferably the electric field has only the axial component and no radial component. Item 25. The method according to any one of Items 1 to 24. 26. The method according to any one of claims 1 to 25, comprising repeatedly performing a cycle of operation, wherein each cycle of operation comprises:
Discharging the ions trapped in the ion trap axially into the ion guide;
Separating the ions ejected in the axial direction within the ion guide, and accumulating and trapping different ions in the ion trap;
26. The method according to any one of claims 1 to 25, comprising: A mass and / or ion mobility analyzer,
An annular or coaxial ion trap arranged and adapted to trap ions; and
An annular ion guide;
A control system,
(I) ions are trapped in the annular or coaxial ion trap, and ions trapped in the ion trap are distributed over the entire circumference in the annular or coaxial ion trap; and (ii) the annular or coaxial ion trap. When at least some of the ions in the annular or coaxial ion trap are axially ejected into the annular ion guide, and when the ions travel along at least part of the length of the ion guide, the annular ion guide So that there are no restrictions on the movement of ions around the periphery, and the ions separate axially as they travel along the ion guide,
A control system which is arranged and adapted;
With
A mass and / or ion mobility analyzer, wherein the electrode configuration of the analyzer is arranged and configured to change the ions from an ion beam having an annular cross section to an ion beam having a non-annular cross section.   28. The analyzer of claim 27, wherein the analyzer is arranged and configured to perform the method of any one of claims 1-26. A method of mass and / or ion mobility analysis comprising:
Trapping ions in an annular or coaxial ion trap;
Discharging at least a portion of the ions axially from the annular or coaxial ion trap into an annular ion guide;
Including a method.

Images